Various methods have been developed for this purpose, most of which are based on the introduction into the room of air which has a lower temperature than the air present in the room, and is therefore capable of extracting thermal energy from the room, and thus of reducing the room temperature. The basis of these known methods is that the air is conveyed mechanically, and fed to the room at various locations, namely either from above or from the side wall or also through the floor. With these known methods, a substantial portion of the entire energy consumption is made up of a mechanical conveyance of the air by fans.
As an alternative to the above mentioned room cooling by air exchange, it has also been proposed to extract heat from the room by cooling at surfaces located in the room, i.e. by means of heat exchange by radiation and inherent convection, but this fails in most cases because suitable surfaces are not available in the room or because in practice only a very slight temperature difference is possible.